Mixed ester plastic additive

ABSTRACT

A plastic additive comprising the mixed ester reaction product of 2,2,4-trimethylpentane-1,3-diol monoisobutyrate, a monohydric alcohol of the formula ROH wherein R is straight or branched chain alkyl of 1 to 12 carbon atoms or benzyl and dimethyl terephthalate. The additive is particularly useful as a processing aid for rigid polyvinyl chloride and as a modifier for thermoplastic acrylic coatings.

United States Patent McCollum et al.

MIXED ESTER PLASTIC ADDITIVE Inventors: Anthony W. McCollum; David C.

Hull, both of Longview, Tex.

Eastman Kodak Company, Rochester, NY.

Filed: Aug. 6, 1973 Appl. No.: 385,759

Assignee:

U.S. Cl. 260/475 P; 260/31.6 Int. Cl. C07C 69/82 Field of Search 260/475P References Cited UNITED STATES PATENTS 1/1973 Mottez et all 260/475 PPrimary Examiner-Lorraine A. Weinberger Assistant ExaminerE. Jane SkellyAttorney, Agent, or FirmEdward R. Weber; Daniel B. Reece, Ill

57 ABSTRACT A plastic additive comprising the mixed ester reactionproduct of 2,2,4-trimethylpentane-l ,3-diol monoisobutyrate, amonohydric alcohol of the formula ROI-l wherein R is straight orbranched chain alkyl of l to 12 carbon atoms or benzyl and dimethylterephthalate. The additive is particularly useful as a processing aidfor rigid polyvinyl chloride and as a modifier for thermoplastic acryliccoatings.

3 Claims, N0 Drawings MIXED ESTER PLASTIC ADDITIVE This inventionrelates to a new class of materials which has been discovered to beparticularly effective as a processing aid for polyvinyl chloride andother polymers and as a plasticizer for acrylic coatings. Moreparticularly, this invention relates to the mixed ester products of anester interchange reaction involving dimethyl terephthalate, amonohydric alcohol and 2,2,4-trimethylpentane-l ,3-diol monoisobutyrate.

Increased use of plastics has resulted in an increased demand forcompositions to modify the end physical properties of the plastics or toimprove the characteristics of the plastic during its processing. Amongthe features required of an additive is the ability to be retained inthe plastic composition and not be extracted by exposure to variouseveryday solvents to which the plastic may be exposed, such as soapywater, food oils, etc. Another desirable feature of the additive is thatit should obtain the desired improvement in any particular physicalproperty without a corresponding degradation in any other importantphysical property of the material. The search for suitable modifiers hasencompassed a broad spectrum of organic and inorganic chemicals.However, almost universally, each additive which has improved processingcharacteristics has also produced a degradation of desirable physicalproperties such as clarity, impact strength, etc.

Therefore, an object of the current invention is to provide a processingaid for polyvinyl chloride which will not result in loss of ultimatephysical properties of the end product.

Another object of the invention is to provide a processing aid forpolyvinyl chloride which is less subject to extraction by solventsnormally encountered.

Yet another object of the invention is to provide a processing aid forpolyvinyl chloride which will result in increased clarity of the endproduct.

These and other objects of the invention will become clear from thefollowing specification and the appended claims.

The composition of the instant invention is the mixed terephthalic esterreaction product of an ester interchange reaction involving dimethylterephthalate, a monohydric alcohol of from i to 12 carbon atoms, and2,2,4-trimethylpentane-l ,3-diol monoisobutyrate, hereinafter referredto as PDIB. The new composition exhibits unique properties as aplasticizer for acrylic coatings and as a processing aid for polyvinylchloride and other polymers. The new composition shows extremepermanence in vinyls and coatings when subject to typical soapy water,oil, and hexane extraction tests.

The composition of the instant invention is prepared by conventionalester interchange reactions with the composition of the end productbeing controlled by the continuous removal of methanol so that the finalproduct has an apparent molecular weight of from about 400 to about1000. The molar ratio of the reactants, i.e., monohydricalcohol/PDlB/dimethyl terephthalate can be varied from about 0.l/l.9/l.0to about 1.9/0.1/1 .0, respectively. A preferred ratio of reactants is1.0/1 .0/1 .0, respectively. Molar ratios outside the above limitsproduce compositions which are essentially either di(PDIB) terephthalateor dialkyl terephthalate and which behave as ordinary plasticizers withconsequent loss of impact strength and increase in flexibility whenadded to polyvinyl chloride. These properties are undesirable for use asa processing aid in rigid polyvinyl chloride.

Monohydric alcohols which may be used in the reaction may be anystraight or branched chain aliphatic or benzyl alcohol of from 1 to12carbon atoms. For purposes of convenience the term alkyl whenever usedin this specification is broadened so as to include benzyl alcohol,according to the preceding definition, un-

less such a breadth is obviously inconsistent with the portion of thespecification involved. Typical monohydric alcohols include methanol,ethanol, normal butanol, isobutanol, normal hexanol, Z-methylpentanol,2-ethylhexanol, 2,2,4-trimethylpentanol, aromatic benzyl alcohol and2,4-diethyloctanol.

A typical preparation would include the ester interchange reaction ofdimethyl terephthalate with isobutanol and PDIB at a reactiontemperature of from about C. to about 200C. using a concentration offrom about 0.05 to 0.4 weight percent of a suitable catalyst such as,for example, dibutyltin oxide, zinc acetate, zinc chloride, stannousoxalate or an alkaline metal alkoxide. The reaction is driven in thedesired direction by distilling methanol from the reaction mixture. Theresultant product is a mixture of diesters including PDIB isobutylterephthalate, diisobuty'l terephthalate, di(PDIB) terephthalate, methylisobutyl terephthalate, and a mixture of bis-terephthalates which arisesfrom the interchange of dimethyl terephthalate with the isobutyrate ofPDIB giving methyl isobutyrate and the mixture of bis-terephthalates.

For convenience hereinafter, the specific product resulting from use ofisobutanol as the monohydric alcohol will be identified as DIBT.Likewise, the generic product resulting from use of any of thepreviously-defmed monohydric alcohols will be identified as DAT.

The chemistry of the reaction is as follows 0:. ROH (CH Cllgll:1lC(Cl-lCH O CCH(Cl-l CH O C CO CH Monohydric PDIB Dimethyl AlcoholTerephthalate /.=I\ (CH CHC0 CH CH 0H (CH CHZHC (CH CH O C\' C0 R (CHCHC 2 Methyl Methanol PDIB Alkyl Isobutyrate terephthalate Mixed DialkylTerephthalate Esters R C through C R' C through C 12 alkyl or benzyl.

12 alkyl, benzyl, or PDIB The 2,2,4-trimethylpentane-l ,3-diol which isa portion of the bis-terephthalate mixture is the result of theparticipation of a portion of the PDIB in a multiple ester interchangewherein 2,2,4-trirnethylpentane-l,3- diol, hereinafter referred to asPD, is formed in conjunction with methyl isobutyrate. The PD then,either directly or more probably as a sequence of ester interchanges,enters into a bis-terephthalate formation and accounts for the highermolecular weight portion of the product mixture. The following generalformula illustrates the type of bis-terephthalate which is formed.

H(CH:5)2 R'O2C CO2CHZC(CH5)a HO2C- -COzR' R alkyl of l-l2 carbons,benzyl, or PDIB.

The basic unit is PD bis-terephthalate which is terminated with a memberselected from the group consisting of C C alkyl, benzyl and PDIB. I

Table I presents a typical product composition and shows a total of 25percent bis-terephthalates. The components in the product mixture wereseparated by gas chromotography and collection of the individualcomponents allowed structural assignment for the observed peaks.

TABLE I Typical Gas Chromotographic Analysis of a Product MixtureMolecular Weight Component Weight Percent Methyl lsobutyl Terephthalate236 3.2 Diisobut lTerephthalate 278 17.5 Methyl DlB Terephthalate 3787.8 PDIB lsobutyl Terephthalate 420 29.2 di( PDIB) Terephthalate 562 9.6

/-=I\ R02C0 o-co( P )QC o o-( R 1 PDRbis(monoa{lkyl terephthalate)Methyl lsobutyl 504 3.1 lsobutyl lsobutyl 546 9.5 PDlB lsobutyl 688 5.3PDlB PDlB 830 7.1 Others 7.0

The apparent molecular weight of the product mix will vary, dependingupon the reaction time, temperature, and the ratio of feed materials.However, for most purposes, the apparent molecular weight will fallwithin a range of from about 400 to about 1000. An apparent molecularweight of 400 represents the lowest average molecular weight for aproduct mix incorporating a mixed PDIB alkyl terephthalate, i.e., if themixture is predominantly PDIB methyl terephthalate (molecular weight378), the average molecular weight of the mixture would be expected tobe 400 or above. At

bis-Terephthalates TABLE II Applicable Weight 7 Percent RangesIngredient Useful Preferred Dialkyl Terephthalate 0.1-50 5-25 PDIB AlkylTerephthalate 10-60 3060 di(PClB) Terephthalate l-60 5-20 PDbis(monoalkyl) terephthalate For purposes of convenience alk'yl isdefined to include the straight or branched chain alkyl groups of from Ito l2 carbon atoms and the benzylring.

The following examples will further illustrate the compositions of thepresent invention and will show the advantages over the prior artmaterials. It should be understood, however, that these examples areillustrative only, and in no way limit the scope of the invention asdescribed in the specification and the appended claims.

Two 2-liter stirred, steam-jacketed reactors are connected in series.Each reactor has a l-inch by 15-inch Penn State packed column withvariable take-off head and condenser attached to it. The reactors arehooked together so that the product is drawn from the bottom of thefirst reactor and fed into the top of the second reactor. The product isthen drawn from the bottom of the second reactor and fed continuously toa gas stripper. The base temperature for the reactors can be varied froml20 to 200C. Feed to the reactors is accomplished through two separatestreams with the monohydric alcohol being fed in one stream, and theother reactants, i.e., PDIB, dimethyl terephthalate and the catalystbeing fed in the second stream. The gas stripper is a l-inch by 36-inchcolumn packed with Berl saddles. Nitrogen at 200C. is fed to the gasstripper to remove low boilers and unreacted alcohols. The base productfrom the gas stripper is the DAT of the instant invention. The overheadfrom the gas stripper can be recycled to the first reactor. Thisoverhead consists identify.

7 8 -continued -continued EXAMPLES EXAMPLES Methyl PDlB Methyl AlkylTerephthalate l 2 5 8 Aikyl Alkyl PDIB Alkyl 5 PDlB Alkyl 18Terephthalate l6 15 31 PDIB PDlB di(PDlB) Terephthalate 8 3 6 *Alkylrefers to the monohydric alcohol used in Feed A (i.e., isobutanol asFeed A becomes isobutyl in chromatographic analysis of product), R 'OC-o /--co( PD)OC- O2R 10 The utility of DAT is obvious from its uniqueand W unexpected properties, and is demonstrated by the Alkyl Alkylfollowing examples. Egg 51) 34 38 DAT is very compatible with polyvinylchloride ho- EXAMPLES mopolymer and copolymers, producing clear plastic13 14 5 material of a very permanent nature. It does not impart Feed Aflexibility to polyvinyl chloride, as normally expected Wm Alcohol,Benzy, PDB with esters, but yields rigid polyvinyl chloride with aethyloctanol lower processing temperature than normally achieved. 12 60For example, di-2-ethylhexyl terephthalate or dibutyl [TIME-gnu 00 90 20terephthalate cannot be used as a processing aid for DimethylTerephthalate, rigid polyvinyl chloride because they impart flexibilityg/hf- Q Q 9 and, at low concentration, poor impact strength. Catalyst,Dibutyltin Dibutyltin Dibutyltin C D AT ff f l oxide Oxide OxideOmPOSIItIOUS containing I o er uti ity or po yvig/hi. 0.2 0.1 0.1 nylchloride applications including plastic bottles, M 25 swimming poolliners, automotive gasketing, perma- Temperature, C. 180 d h lDistillate g/lm 25 22 nent wire coatings an ot er mo ding, extru ing, orResidence Time, hr. 3.0 3.0 5.0 calendering applications requiringpermanence and/or Reactor 2 l Tem erature "c 180 180 190 c an Disfifiateg/hn 6 8 Compositions are given below incorporating DAT as ResidenceTime, hr. 2.0 2.0 2.0 30 a processing aid for rigid polyvinyl chloride.The test W results from the Brabender and two roll mill indicate ggfifigi'a the rapidity at which polyvinyl chloride reaches a melt Distillate,g/hr. stage. Shorter times are desired by a processor. Torque Product,g/hr. is i n t w in Molecular weight 5) 600 620 an ndicatio of he orkrequired du mg process g. Gas chromatographic 35 Normally, additives topolyvinyl chloride should only Analysis, Wt minimally increase thetorque requirements. Methyl Alkyl* Terephthalate 6 7 Dialkyl Tere-EXAMPLE 16 A B C D E Polyvinyl Chloride Resin, grams I00 100 I00 100 100Ba-Cd Stabilizer, grams 2 2 2 2 2 Stearic Acid, grams 0.5 0.5 0.5 0.50.5 Processing Aids, grams 0 Product from Example 5,

PDlB lsobutyl Terephthalate 5 Product from Example 1,

PDIB Methyl Terephthalate 5 Product from Example 9,

PDlB Z'MethyIpentyI Terephthalate 5 Product from Example 13,

PDlB 2,4-Diethyloctyl Terephthalate 5 Two Roll Mill Band (Fusion) Time,350F., min. 16 3 3 3 3 Brabender Plastigraph Fusion Time, 350F., min.

ASTM D2538 l9 4 4 4 4 Torque at Fusion, 103 meter-grams ASTM D2538 2.12.3 2.2 2.3 2.3

Note: Equivalent results are noted when the products of Examples 2, 3,4, 6, 7, 8, 10, ll, l2, l4 and I5 are tested in a similar manner.

phthalate l9 l0 Methyl PDlB EXAMPLE 17 Ea *Xi'gi 5 The physicalproperties of rigid polyvinyl chloride gereplihalate 2 5 are usuallyimpaired by the addition of an additive such i(PD Terephthalate 7 7 65as dioctyl phthalate, di(2 ethylhexyl) terephthalate, or 65 dibutylterephthalate. Addition of DAT provides a R'O2C0 ;lCO(PD)QC.-.\ "402whigher impact resistance with insignificant effect on heat deflectiontemperature and strength properties as illustrated by the followingexample.

. ASTM D648 ASTM D638 ASTM D256 Heat ASTM D790 Tensile lzod Impact,23C., Deflection Flexural, psi Strength, psi

. ft.-lb./in. Temp. at X 10 X Formulation Notched Unnotched 264 psi, C.Modulus Strength Yield Fracture Example 16-A (Control) 0.7 10 60 4.6 1.38.4 5.4 Example 16B 0.7 12 59 4.8 1.4 10 5.6 Example 16 C 0.6 10 60 4.71.4 9.9 5.6 Example 16-D 0.7 10 61 4.8 1.4 10 5.7 Example 16-E 0.7 10 604.8 1.4 10 5.6 Di(2-ethylhexy1) Phthalate, 5 phr 0.2 3 55 4.4 1.3 9 4.8Di(2-ethylhexyl) Terephthalate, 5 phr 0.2 3 56 4.4 1.2 8.5 4.9 DibutylTerephthalate, 5 phr 0.2 3 55 4.2 1.3 8.4 5.0

EXAMPLE 18 As illustrated in the following examples, DlBT givesthermoplastic acrylic coatings unusually hard surfaces without unduesacrifice in other important coating properties. The Tukon hardness ofthe acrylic coating incorporating PDIB isobutyl terephthalate is 50percent harder when compared with neopentyl glycolphthalate-adipate, atypical polyester plasticizer.

Wt. Acrylic resin (40%)* 26.0 EAB 531-1 (Product of Eastman KodakCompany) 3.5 Plasticizer 4.0

Case A: Example 5, DlBT Case B: Neopentyl glycol-phthalate-adipateDioctyl phthalate 0.4 Alcoa 726 aluminum flake (65%) 0.3 Blue pigmentdispersion 0.5 Toluene 21.5 Acetone 19.6 Ektasolve EE Acetate (Productof Eastman Kodak Company) 24.2 100.0

Dissolved in 70/30 mixture of toluene and acetone. The acrylic resin isa copolymer of isobutyl methacrylate and methyl methacrylate present inthe ratio of 85/15.

"40% Phthalocyanine Blue, 50% EAB 531-1. 10% butyl benzyl phthalate.

The above paint (19 percent solids) was reduced to 17 seconds No. 4 FordCup with a 40/30/30 blend of toluene/acetone/Ektasolve EE acetate.

Case A Case B Humidity Resistance (Cleveland Cabinet.

24 hr.). gloss retention 90 90 UV Ex osure (QUV), gloss retention 80 8OCycle rack. cycles 15 Surface Distortion (Spotting), F. 143 140 lmpactResistance (1.8 mils), ft./lb.

Direct 8 8 Reverse 2 2 Tukon Hardness, ft./1b. (ASTM D1474-57T) 15.7 10

Equivalent results were achieved when the products of Examples 1-15 weretested in a similar manner. The test methods, humidity resistance, andultraviolet light exposure indicate high gloss retention when DlBT isused as a plasticizer in acrylic coatings. Humidity resistance isdetermined in a Cleveland QTC Cabinet manufactured by the Q PanelCompany. The test cycle is 24 hours at 150F., 100% relative humidity.Ultraviolet resistance is determined in a QUV Cabinet also manufacturedby the Q Panel Company. The test cycle is 8 hours exposure to UVradiation at 155F. and ambient humidity plus 4 hours additional exposureat 110F. and 100% relative humidity. Cycle cracking is a measure of thenumber of times a coated panel can withstand a cycle of 24 hours at100F. (100 percent relative humidity) followed by 20 hours at 0F. and 4hours at room temperature (ambient humidity). Surface distortion is thetemperature at which a one percent egg albumin solution permanentlystains and causes micro cracking of the coating. Impact resistance isthe amount of force, applied through a /8 inch ball, which causes thecoating to separate from the substrate. The Tukon hardness of a fusedcoating was evaluated by 21 Wilson Tukon Tester. DlBT contributes to a50 percent harder film surface than Case B and other commercialpolyester plasticizers. The magnitude of the hardness difference isunexpected.

Other uses of DAT can be enumerated. DAT is compatible with polyolefinsin quantities up to 12 percent, and also serves as a processing aid inthis use. DAT is also compatible with poly(ethylene terephthalate) andlowers the processing temperature of this molding plastic. DAT iscompatible with other resins including poly(methyl methacrylate),poly(pivalolactone), cellulosics, and epoxy resins, and serves to reducethe melt flow index and/or processing temperature. This permits eithermore rapid processing or processing at lower temperatures and results inarticles with smoother surfaces as a result of the improved flowcharacteristics.

Although the invention has been described in considerable detail withreference to certain preferred embodiments thereof, it will beunderstood that variations and modifications can be effected withoutdeparting from the spirit and scope of the invention as describedhereinabove.

We claim:

1. The mixed ester reaction product of2,2,4-trimethylpentane-l,3-diol-monoisobutyrate, a monohydric alcohol ofthe form ROl-l where R is straight or branchchained alkyl of 1 to 12carbon atoms or benzyl, and dimethyl terephthalate wherein the molarratio of the reactants is from about 0.1/1 9/10 to about 1.9/0.1/1.0respectively and which mixture has an apparent molecular weight of fromabout 400 to about 1000.

2. A composition of matter according to claim 1 wherein the terephthalicesters are present in the following percentages by weight:

1 1 1 2 wherein the term alkyl corresponds to the R of the cominuedmonohydric alcohol. diol monoi s ogu t rate) 3040 3. composition of:matter according to claim 2 Elifififg g ifif wherein the terephthalicesters are present in the fol- 3;; m ififigi y lowing percentages byweight: 5 2,2, -trimethylpentane-l,3-diol bis(monoalkyl terephthalate)l25.

dialkyl terephthalate -25 (2,2,4-trimethylpentane-l.3-

1. THE MIXED ESTER REACTION PRODUCT OF2,2,4-TRIMETHYLPENTANE-1,3-DIOL-MONISOBUTYRATE, A MONOHYDRIC ALCOHOL OFTHE FORM ROH WHERE R IS STRAIGHT OR BRANCH-CHAINED ALKYL OF 1 TO 12CARBON ATOMS OR BENZYL, AND DIMETHYL TEREPHTHALATE WHEREIN THE MOLARRATIO OF THE REACTANTS IS FROM ABOUT 0.1/1.9/1.0 TO ABOUT 1.9/0.1/1.0RESPECTIVELY AND WHICH MIXTURE HAS AN APPARENT MOLECULAR WEIGHT OF FROMABOUT 400 TO ABOUT
 1000. 2. A composition of matter according to claim 1wherein the terephthalic esters are present in the following percentagesby weight:
 3. A composition of matter according to claim 2 wherein theterephthalic esters are present in the following percentages by weight: